The present invention relates to a method of separating hydrogen ion, a method of analyzing hydrogen ion, and an ion chromatography apparatus. More specifically, the invention of the present application relates to a novel method of separating and analyzing hydrogen ion, for which selective separation and accurate quantification have been considered difficult; these methods enable the selective separation of hydrogen ion from sample aqueous solutions and the quantitative analysis of hydrogen ion by ion chromatography; the present invention also relates to an ion chromatography apparatus that enable such methods.
Hydrogen ion is believed to be the most fundamental and important substance in various fields such as life science. Namely, it is impossible to understand chemical reactions, chemical equilibrium, electric chemical phenomena of solution systems or life processes in organisms, without considering the presence and chemical phenomenon of hydrogen ion. However, even though hydrogen ion is a fundamental and important substance, separation of hydrogen ion has previously been considered very difficult.
On the other hand, as a method of quantifying and measuring hydrogen ion,pH titration and pH meter are widely used. However, in these methods, measurement with high sensitivity and high precision is considered difficult. Therefore, a novel quantification and measurement method that enables the measurement of hydrogen ion with high sensitivity and high precision has been desired.
The invention of the present application has been accomplished in view of the matters as described above, and its subject is to provide a novel method of separating hydrogen ion and a novel method of analyzing hydrogen ion that enables the selective separation of hydrogen ion from sample aqueous solutions and the quantitative analysis of the separated hydrogen ion with high sensitivity and high precision, as well as an ion chromatography apparatus for such methods.
In order to solve the above-mentioned subject, the invention of the present application firstly provides a method for separating hydrogen ion selectively by chromatography, which comprises using a substance with a functional group which is a conjugate base (Axe2x88x92) of an acid (HA) as a stationary phase, and using an electrolyte which contains a cation that exhibits higher ion exchanging force than hydrogen as an eluent.
Secondly, the invention of the present application provides the method for separating hydrogen ion of claim 1, wherein the separation of trace amounts of hydrogen ion in an aqueous sample solution is enabled by pre-protonating the conjugate base (Axe2x88x92), which is the functional group of the stationary phase.
Thirdly, the invention of the present application provides a method for analyzing hydrogen ion, which comprises quantitatively analyzing the hydrogen ion separated by the above methods, and fourthly, such method for analyzing hydrogen ion, wherein the hydrogen ion is quantitatively analyzed by electric conductivity measuring method or electrode detecting method.
Fifthly, the invention of the present application provides an ion chromatography apparatus that separates hydrogen ion selectively, which comprises a separation column stationary phase that contains a substance having a conjugate base (Axe2x88x92) of an acid (HA) as a functional group, and an eluent that contains an electrolyte containing a cation that exhibits higher ion exchanging force than hydrogen; sixthly, the invention of the present application provides such ion chromatography apparatus, wherein part of the conjugate base (Axe2x88x92), which is the functional group of the stationary phase, is pre-protonated (AH), thereby enabling the separation of trace amounts of hydrogen ion in an aqueous sample solution.
Further, seventhly, the invention of the present application provides the above ion chromatography apparatus, which further comprises an apparatus for the quantitative determination and analysis of the separated hydrogen ion; and eighthly, the invention of the present application provides the ion chromatography apparatus, wherein the apparatus for the quantitative determination and analysis is an electric conductivity measurement apparatus or an electrode detecting measurement apparatus.